The meteoroid that exploded over Russia’s Ural Mountains Friday — shattering windows and injuring hundreds — was the biggest atmospheric explosion in more than a century and the largest ever to occur near a populated area, according to an astronomy professor at the University of B.C.

Professor Brett Gladman estimated the power of Friday’s blast at about 300 kilotons, the equivalent of “more than a dozen atomic Hiroshima bombs” and the most powerful such explosion since 1908, when a much larger object from space exploded over an unpopulated area of Siberia.

“This is a serious, serious event,” said Gladman. “Such an event has never happened over a populated centre in recorded human history.”

While details on Friday’s explosion are still being gathered, Gladman said it appears the meteoroid was about 10 to 15 metres in diameter — about the size of a city bus — and that it hit the atmosphere travelling faster than the speed of sound.

As it plowed into the atmosphere, the meteoroid produced extreme heat and the glowing trail seen in so many amateur videos Friday. Then, the atmospheric pressure became so extreme that the meteoroid fragmented in a “terminal burst” about 20 kilometres above the ground.

Gladman said the shattered windows that caused most of Friday’s injuries were due to the shock wave that followed, which — because light travels faster than sound — arrived a few seconds after residents saw the explosion.

Meteorites, the remnants of the exploded meteoroid, may well have fallen to the ground and will be discovered later, he said.

Had Friday’s meteoroid struck the earth, instead of exploding overhead, the damage would have been much more severe.

“The earth’s atmosphere is basically functioning as a shield for us which prevents these objects from hitting the ground at high speed,” said Gladman. “If they hit the ground at supersonic speed, you have the dust going up into the atmosphere — a mini-nuclear-war kind of scenario. So it is much more dangerous if it reaches the ground at high speed.”

Gladman said the last known meteoroid to hit the earth was 20,000 years ago near the Grand Canyon.

There are nearly 200 documented impact craters on earth. However, none are in B.C.

Gladman said meteoroids are as likely to hit one place on earth as another. However, because B.C.’s geology is relatively new, it’s harder to find evidence of craters here than in places with more ancient parts of the earth’s crust like Australia or the Canadian Shield.

B.C.’s geology also makes it a lot harder for researchers like Gladman to find meteorites that have fallen to earth.

“Somewhere in B.C. you’ll probably have a meteorite fall every year. But, as you can imagine, B.C. is pretty heavily forested,” he said.

Astronomers on the Prairies have a much easier job, said Gladman, because “black meteorites on fresh snow are pretty easy to find”.

While many people are calling what exploded over Russia Friday a meteor, that’s not quite correct, said Gladman.

When an object is hurtling through space and coming through the atmosphere, it’s called a meteoroid, he said. The fragments left over after an explosion are meteorites.

The term meteor, on the other hand, is only used to describe the visible light that can be seen as the meteoroid travels through the atmosphere.